


The Holy Water Test

by Hiffuu



Category: Ao no Exorcist | Blue Exorcist
Genre: At least hinted at, Demon Okumura Yukio, Gen, Injury
Language: English
Status: Completed
Published: 2019-02-16
Updated: 2019-02-16
Packaged: 2019-10-29 15:29:54
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 2,672
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/17810627
Author URL: https://archiveofourown.org/users/Hiffuu/pseuds/Hiffuu
Summary: Yukio enters the abandoned warehouse once again to conduct even more experiments pertaining to his recent demonic developments. This new one, while less extreme, may yield some interesting results.





	The Holy Water Test

Footsteps echoed through the dimly lit alleyway, the only light source being a single torch powered by batteries nearing the end of their use and the large full moon hanging high into the cold night sky.

Yukio Okumura had tread this littered path countless times, not letting the darkness of the abandoned streets bother him any longer. He had more important things weighing on his mind to worry about than something as minuscule as the dark and knew he’d be capable of handling himself if any issues arose.

However the young teen still kept advancing forward quietly despite this knowledge. Knowing deep down that he shouldn’t be here and if he were to be spotted his experiments would have to unfortunately cease, something he could not risk happening. Not now.

The footsteps eventually came to a halt as Yukio finally reached his destination. His grip tightening on the strap of the satchel that sat by his hip, the contents clinking with the sudden action. The familiar sight of the warehouse that stood before him should have eased his anxiety but instead increased it as he viewed the array of shattered windows that lined the tattered walls. Atop the roof stood a railing where he had before gripped and stared out from a number of times, gazing into the dark abyss of the ground below and trying his hardest to plunge himself down into it.

He..still hasn’t managed to do it.

An annoyed grunt left the boy at the thought as he turned his head away from the walls and instead to the broken down ajar entryway. He stomped as quietly as one could through the door, making sure not to catch himself on the sheet of metal that stuck out from the side. Yukio was still recovering from when the offending sheet had sliced him along his calf during his last visit here. He could thankfully cover the injury up by saying he had received it from a mission and luckily for him his brother was gullible enough to buy it.

However there was at least one thing he could rule off from his demonic experiments, and it was that he did not in fact elicit any advanced healing.

Unfortunately.

Narrowly missing the sheet of metal he trudged further into the warehouse, his boots crunching against debris and shards of broken glass that lay on the cement from the broken windows above. Demons that still littered the crevices of the building now became well aware that their intruder had found his way back once more. Yukio had taken care of the bigger threats by force when he had first arrived here and knew that the lesser demons wouldn’t even attempt to bother him, choosing to always stick to the shadows and allowing him to go about his business undisturbed.

That is unless they wanted to stare into the relentless barrel of his firearms.

Yukio made his way to one of the cement pillars resting in the center of room; clearing the surrounding area and removing the satchel slung around his shoulder. He sunk his body downwards until he reached the ground, leaning his back against the cool cement and letting himself breath in the stale air that filled the murky room. Luckily for him the light source from the full moon dipping in from the multiple broken windows allowed him to see his surroundings clearly enough so he wouldn’t be needing his torch.

Yukio clicked open his satchel, rummaging around in it’s contents for the very vial that was clinking earlier; getting straight to work. His hand eventually found itself curled around the bumpy glass texture of the container as he withdrew it from the bag. Holding it up towards his face as he viewed its contents which began to shine brightly in the moonlight through it’s crystal clear particles. This was definitely what he was after.

A full vial of recently blessed holy water.

Uncorking the glass lid and resting it at his side Yukio noticed a slight bustle within the shadows in the corners of the room. The demons must have caught a whiff of the contents deemed deadly to them as Yukio sat indifferent, even bringing the vial close to his nostrils to take in the scent of the water. It smelt like nothing, odourless. Another thing to cross off his list.

Not lingering on this minor detail Yukio proceeded with the experiment that he had planned. It was most likely futile and would likely yield results he already knew, but he wanted to test it for his own peace of mind.

Due to these demonic developments would he be subjected to the effects of holy water like any other demon? Like his brother? He wanted to know.

Yukio brought forth his open left hand and began slowly tipping the blessed liquid onto the rough and calloused skin of his palm and fingers. He watched the water run along his hand, trickle through the gaps between his fingers and off the edges of his palm.

Nothing.

He didn’t feel anything other than regular water lapping softly against skin. Hm.

Honestly the teen wasn’t surprised, it was what he expected. Relief muddled with mild disappointment flooded his emotions as he flicked the left over contents off his hand and rubbed it along his jacket.

He always carried holy water grenades on him in case of emergencies and they definitely came in handy when in a tight pinch. However the blast from the grenade is unpredictable and there is always splash back, usually drenching the exorcist as well as the demon when used depending on the distance. That’s why Rin would never be given them to use, even during their training sessions at the academy. So he supposed that at least he could still use them to fight with.

Although Yukio didn’t feel like giving up just yet. He had other more important experiments to test which would most likely present better results, however he had all night and not wanting to admit it, he felt more tired than usual. Opting to rest against the cement pillar some more he carried on with the holy water test.

Maybe other areas could be affected worse than others..?

This brought Yukio’s attention to his eyes, the root of this whole problem.

He lacked eye drops so instead brought the vial above his head and tipped the contents over his hair, thinking that covering his whole head in the process will cover other areas. Water dripped from the locks of his fringe and traveled along his face, gliding down his nose and cheeks while pooling along his eyelashes and lips. He felt the water enter his open eyes, trying to resist the urge to blink. Even just a little bit of water should be enough since it’s hitting the source of the demonic energy.

However nothing happened except from a mild irritation that began to make his skin itch. Although he wasn’t sure if that was completely due to the water or if it was just from the horrid filthy state the warehouse was in, letting the dust in the air cling to him due to the moisture now resting against his skin.

Blinking and rubbing away said moisture Yukio sighed. This was going nowhere, if the source wasn’t being affected then what even would? He racked his brain but in the end came up empty.

The water just wasn’t going to affect him simple as that.

Yukio angrily slumped against his legs, removing his tucked pants from within his boots and rolling them up past his knees. He felt defeated but still had some water left in the vial and felt like getting rid of it all out of frustration.

Complete silence filled the area as Yukio now watched the water trickle down his right knee, catching and dripping off the hairs of his leg as it made its way down to his boot. Yukio felt oddly relaxed as he stared, thinking that somewhere deep down he was relieved once again by the failure.

The young exorcist felt his eyes grow heavy, borrowing his face deeper into his arms that were resting against his knees. He was just..so exhausted..with everything...when can it all just end..

_**“! ! !”** _

Before Yukio managed to drift off his eyes shot open in shock, his right leg suddenly kicking outwards due to the sudden pain shooting up his calf. Sucking in a deep breath of stale air he clenched his jaw tightly shut, wincing at the pain. Said pain was immense, like his leg had been covered in burning hot coals, pushing and prodding into every pore that dotted his skin.

Yukio’s hands quickly found their way to his leg, cradling the burning pain with strangled moans escaping from his still clenched teeth.

_This wasn’t right._

The water had found its way along the side of his calf and into the gash caused by the sheet of metal. Of course exposing any kind of water to an open wound can elicit some levels of pain and discomfort, but nowhere near this extreme. Not to the point of burning flesh.

Yukio shakily detached his hands from his leg as the pain subsided slightly, still raw but bearable enough. He reached for the fabric of his pant leg and pulled it down to dab at the still moist area, drying it of water before slowly lifting it up to survey the damage.

While the area around the gash was already previously red beforehand, it had increased in size with blisters now coating the edges of the currently wet peeling skin that skimmed around the outer edges of the cut.

However the one thing that stood out the most was the steam. A light trail of steam rose from the charred skin, now slowly shrinking after finally dampening out the ‘fire’.

Yukio bit back a noise that was trying to escape from his throat at this revelation. It felt too scared...too feral to escape from lips such as his. However he couldn’t hold back the pinprick of tears that began to form at the rims of his eyes. He had just experienced a pain no human should ever feel from the substance he used. A liquid that was meant to bless and heal instead cursed and injured his flesh.

Yukio wasn’t sure what to feel at that very moment as his mind went blank and his hands began subconsciously rubbing soft circles into the small raw patches of blistering skin.

A sore comfort.

He then regained a trail of thought. On one hand this experiment had in the end helped his research, allowing him to know more about the current changes in his body.

He definitely wasn’t human, at least not to the extent that he had thought. He still wanted power, badly so, but was it worth trading his humanity over?

...Perhaps…

Although in the end he still wasn’t sure, the exhaustion from before hitting him like a pile of bricks as Yukio felt the small tears resting at his eyes finally slip down his cheeks. What a miserable and cowardly mess he was.

His own brother carrying Satan’s flame of all things had been completely dowsed in holy water before, covering his awakened demon body from head to toe and allowing the holy liquid to perform it’s true purpose perfectly...and Rin brushed it off like it was nothing, he was fine.

Of course he fucking was.

While on the other hand Yukio could only seem to feel its effects with exposure to his inner flesh, almost like he was wearing a raincoat for protection. Even with such a tiny amount of water exposed to the wound he still reacted and winced in pain.

_Pathetic._

Yukio allowed his mind to go black once more and continued to sit silently in the dusty atmosphere of the warehouse for a while, watching what he could see of the lesser demons crawl around in the shadows.

Suddenly he felt a prodding nudge from a pointed object near the area of his burnt gash. Whipping his head down to the source, his eyes glinting in the moonlight that washed over his hunched body as he took in the view of demon.

Said creature taking the full brunt of Yukio’s piercing gaze jumped back, beady eyes wavering as it shakily withdrew its claw.

It was a lesser demon that had managed to scrounge up enough courage to leave the safety of the shadows and venture towards the intruding nephilim.

It was quite small in appearance with the size and figure being similar to that of a rat. It’s fur was matted and pitch black, trailing off the tips of the strands were soft wisps of smoke. Two curved horns were adorned between the small yet fluffy ears on the top of its head while it’s nubby hand like paws with thick dull claws trembled against the cement. It’s naked arrow tipped tail wrapping around it’s body for protection.

Yukio squinted at the demon trying to picture the name of it in his mind but nothing was appearing, but at the same time he really couldn’t care less.

Eventually gaining its courage once more the lesser demon gazed up at Yukio, its beady eyes flicking towards the vial of discarded holy water and then to his face. It’s eyes were filled with...concern? As it’s nose twitched towards his still exposed wound, watching the now very small trails of smoke wither into the air.

The young exorcist immediately pieced things together. He must have appeared even more pathetic than he had thought if a low class rat was trying to sympathise with him.

Yukio couldn’t hold it back any longer, allowing the caged growl from earlier erupt from his throat, sounding as foreign as he thought it would. Flashing his blunt teeth in a snarl as he glowered at the demon, not wanting it to stare at him anymore with those sorrowful eyes.

The demon rat’s fur stood on end, fluffing up as it hissed back while snapping its own sharp fangs. The demonic growl from Yukio obviously initiating something as the creature eventually took off, scurrying back into the shadows. Yukio gave a huff as he eyed the rat as it fled, unaware of what he had done but glad it seemed to have worked regardless.

Yukio had honestly had enough.

The teen angrily reached for the fabric of his pant leg once more and rolled it down, wincing slightly as it unfortunately grazed against his wound. After tucking the material into his boot he lent his head against the cement pillar, once again staring off into the distance.

No other demon seemed to bother to approach him as he noticed that the rustling in the shadows had hushed. An eerily silence filling the room.

He guessed that everyone else had enough too.

Yukio sighed knowing that he should just go and leave the other experiments to another time.  
This new information was good enough and was rattling his already messy mind. He picked up the discarded holy water vial, caressing it in his hand as he traced the lid of the bottle with his finger. Reaching for the glass cap and pulling it open once more.

He wasn’t thinking. He didn’t want to think as he began to pour what little leftover contents there were onto the hand he hadn’t tried before, knowing a few small cuts graced his fingers from recent exorcisms. Of course it stung but no where near as bad as the large fresh gash. It began to feel like some kind of morbid fascination as he finally let the last of the water drip from his fingers and onto the cement floor.

How he was going to find a way to omit holy water from his arsenal without raising suspicion was a thought for another day. As Yukio packed away his belongings and finally rose from his divinely saturated area, leaving the experimental warehouse once more.

**Author's Note:**

> I've been wanting to write a fanfic with Yukio for a while and thought it would be interesting to see the anti-demonic substances he's used for many years for protection begin to turn against him.
> 
> Demonic Yukio content is just really cool and honestly Yukio as a whole is just a really interesting character in general.
> 
> I don't write very much so I hope things have turned out decent enough to read. Thank you very much for reading!


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